1. They practice gratitude.

Instead of focusing on their burdens or what they don’t have, mentally strong people take stock of all the great things they do have. There are a whole host of ways to practice gratitude, but a simple way to start is to think of three things you’re grateful for each day. You can also start a gratitude journal to jot down all the good things you experienced throughout the day or adopt gratitude rituals like giving thanks before a meal.

2. They aren't afraid to say, "No."

Difficulty in saying no can lead to stress and burnout, and many mentally strong people know that and think critically before accepting every social invitation or helping colleagues out on projects. This way, they can make sure to complete their own work first and not overextend themselves.

3. They overcome their inner critic.

If you think you’re a failure, you may be more likely to fail. It can be a self-fulfilling prophecy. Use that idea to your advantage by believing you’re going to succeed. This can be a challenge, but it’s possible if you pay attention to your thoughts. Don’t ignore those negative thoughts -- acknowledge them, then do something positive to distract yourself.

Take a look at the evidence on both sides. By jotting down the good and the bad, you’ll notice that some of those negative thoughts are irrational. Find balance -- rather than beat yourself up, look at your flaws as ways to improve.

4. They expose themselves to pain.

Muhammad Ali once reportedly said that he didn't count all of his sit-ups; he only started counting them when it hurt because those were the ones that counted.

Mentally strong people are often willing to endure pain as long as there's a purpose. They don’t go through a challenging workout, for example, just to prove how tough they are -- they do it to build strength.

5. They create their own definition of success.

When I started my first business, things were tough -- especially when it failed. It was especially difficult to see my neighbors purchasing new cars and high school friends posting pictures of their travels. For them, maybe that was the definition of success. But even though my business failed, I told myself I was still successful. I had an amazing wife and knew I could pick myself up. Today, I’m a successful entrepreneur.

That's not to boast. My point is that the successful have their own definition of success. For example, I work with freelancers who don’t make what some would consider a lot of money. But they see themselves as successful because they’re doing what they love with a flexible schedule.

6. They delay gratification.

Delaying gratification could be paramount to success. That’s why people with mental strength have the strength to think long-term and do just that. They know that results only take place after they’ve put in the time and effort.

7. They don’t blame others.

Mentally strong people avoid blaming others for their mistakes or shortcomings. They take full responsibility for their actions. Doing so means they don’t give power to others, remain stuck or become negative people.

8. They practice realistic optimism.

Mentally strong people tend to be optimistic, but they also understand that they can’t be overly optimistic. As Dr. Mara Karpel explains, “It’s unproductive to believe that challenges will magically disappear or goals will be manifested without taking any action in the real world.”

Mentally strong people practice realistic optimism instead. This means they take into account the challenges facing them and focus on what they can do to accept or overcome those realities. Many start with scheduling things ahead of when they need to be done so that they have wiggle room.

9. They acknowledge their limitations.

Although the mentally strong push themselves, they also know when it’s time to throw in the proverbial towel. They’re aware of their weaknesses, and they don’t hesitate to ask for help when needed.

While some leaders are hesitant to show vulnerability, doing so enables them to learn more and become better than they were yesterday. Enhancing their skill set is more important than protecting their ego.

10. They don’t compare themselves to others.

Mentally strong people are intentional about how they spend their time and energy, and they know it's futile to use it worrying about what others are doing. Feelings like jealousy and resentment aren’t just exhausting -- they’re essentially pointless.

The mentally strong appreciate others and celebrate their accomplishments with them, and that optimism is often a win-win for everyone. According to a Harvard University study, a sense of optimism may be correlated with a reduced risk from dying of major causes, such as cardiovascular disease.

11. They don't run from fear.

Most people run away from their fears, but not the mentally strong. They not only seek them out but also, in a way, enjoy the fear as a method of getting out of their comfort zone. As a result, they often experience new things, meet new people and learn more about themselves.

12. They respect, and even like, their competitors.

Mentally strong people aren’t afraid, intimidated by or jealous of their competitors. In fact, many respect and even like them, realizing that their competitors can be their greatest teachers. Mentally strong people know to pay attention to what the competition did right or wrong and use it to see what differentiates them -- as well as use it as inspiration for their own next move.

Steve Jobs and Bill Gates reportedly had a strained relationship. However, both men ultimately supported and respected each other, with Gates once saying, "I’d give a lot to have Steve’s taste." Jobs admitted, "I admire him for the company he built -- it’s impressive -- and I enjoyed working with him. He’s bright and actually has a good sense of humor."

Becoming mentally strong doesn't happen overnight, but it's worth the journey. It can make you -- and your business -- resilient enough to withstand anything life throws at you.

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